Hi Jan,
On 05/02, Jan Kara wrote:
> Commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as
> synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
> definitions. generic_make_request_checks() however strips REQ_FUA and
> REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
> write cache and thus write effectively becomes asynchronous which can
> lead to performance regressions.
>
> Fix the problem by making sure all bios which are synchronous are
> properly marked with REQ_SYNC.
>
> Fixes: b685d3d65ac791406e0dfd8779cc9b3707fea5a3
Looks good to me. Thank you for the patch.
BTW, does this need cc to stable?
Cc: stable@xxxxxxxxxxxxxxx # 4.9+
Thanks,
> CC: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> CC: linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> fs/f2fs/data.c | 2 +-
> fs/f2fs/segment.c | 2 +-
> fs/f2fs/super.c | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 1602b4bccae6..dd24476e8d2c 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -309,7 +309,7 @@ static void __f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
> if (type >= META_FLUSH) {
> io->fio.type = META_FLUSH;
> io->fio.op = REQ_OP_WRITE;
> - io->fio.op_flags = REQ_META | REQ_PRIO;
> + io->fio.op_flags = REQ_META | REQ_PRIO | REQ_SYNC;
> if (!test_opt(sbi, NOBARRIER))
> io->fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
> }
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 29ef7088c558..0c24cec55dc9 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -416,7 +416,7 @@ static int __submit_flush_wait(struct block_device *bdev)
> struct bio *bio = f2fs_bio_alloc(0);
> int ret;
>
> - bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
> + bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
> bio->bi_bdev = bdev;
> ret = submit_bio_wait(bio);
> bio_put(bio);
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 96fe8ed73100..fa5af1f04798 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1307,7 +1307,7 @@ static int __f2fs_commit_super(struct buffer_head *bh,
> unlock_buffer(bh);
>
> /* it's rare case, we can do fua all the time */
> - return __sync_dirty_buffer(bh, REQ_PREFLUSH | REQ_FUA);
> + return __sync_dirty_buffer(bh, REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
> }
>
> static inline bool sanity_check_area_boundary(struct f2fs_sb_info *sbi,
> --
> 2.12.0
